#!/usr/bin/python
# -*- coding: utf-8 -*-
from xencoder import xencoder
from yencoder import yencoder
from tencoder import tencoder

if __name__ == "__main__":
    x = float(input())
    # y = float(input())
    # t = float(input())
    xybit = input()
    # tbit=input()
    xstart = float(input())
    xend = float(input())

    print xencoder(x, xybit, xstart, xend)
